<html>

<head>
  <title>Canvas tutorial</title>

  <style type="text/css">
    canvas {
      border: 1px solid black;
    }
  </style>
</head>

<body>
  <canvas id="tutorial" width="150" height="150"></canvas>
</body>

<script>
  var convas = document.getElementById('tutorial');
  if (canvas.getContext) {
    var ctx = canvas.getContext("2d");
  }
  ctx.fillStyle = "rgb(200, 0, 0)";
  ctx.fillRect(10, 10, 55, 50);

  // ctx.fillStyle = "rgb(0, 0, 200, 0.5)";
  
</script>

</html>